<template>
  <div class="drag" ref="dragDiv">
    <div class="drag_bg"></div>
    <div class="drag_text">{{confirmWords}}</div>
    <div ref="moveDiv" @mousedown="mouseDownFn($event)" :class="{'handler_ok_bg':confirmSuccess}" class="handler handler_bg" style="position: absolute;top: 0px;left: 0px;"></div>
  </div>
</template>

<script>
  export default {
    data(){
      return {
        beginClientX: 0,           /*距离屏幕左端距离*/
        mouseMoveState: false,     /*触发拖动状态  判断*/
        maxWidth: '',               /*拖动最大宽度，依据滑块宽度算出来的*/
      confirmWords: '向右拖动滑块验证',  /*滑块文字*/
      confirmSuccess: false           /*验证成功判断*/
    }
    },
    methods: {
      //mousedown 事件
      mouseDownFn:function (e) {
        if(!this.confirmSuccess){
          e.preventDefault && e.preventDefault();   //阻止文字选中等 浏览器默认事件
          this.mouseMoveState = true;
          this.beginClientX = e.clientX;
        }
      },
      //验证成功函数
      successFunction(){
        this.confirmSuccess = true;
        this.confirmWords = '验证通过';

        if(window.addEventListener){
          document.getElementsByTagName('html')[0].removeEventListener('mousemove',this.mouseMoveFn);
          document.getElementsByTagName('html')[0].removeEventListener('mouseup',this.moseUpFn);
        }else {
          document.getElementsByTagName('html')[0].removeEventListener('mouseup',()=>{});
        }
        document.getElementsByClassName('drag_text')[0].style.color = '#fff';
        document.getElementsByClassName('handler')[0].style.left = this.maxWidth + 'px';
        document.getElementsByClassName('drag_bg')[0].style.width = this.maxWidth + 'px';
      },
      //mousemove事件
      mouseMoveFn(e){
        if(this.mouseMoveState){
          let width = e.clientX - this.beginClientX;
          if(width>0 && width<=this.maxWidth){
            document.getElementsByClassName('handler')[0].style.left = width + 'px';
            document.getElementsByClassName('drag_bg')[0].style.width = width + 'px';
          }else if(width>this.maxWidth){
            this.successFunction();
          }
        }
      },
      //mouseup事件
      moseUpFn(e){
        this.mouseMoveState = false;
        var width = e.clientX - this.beginClientX;
        if(width<this.maxWidth){
          document.getElementsByClassName('handler')[0].style.left = 0 + 'px';
          document.getElementsByClassName('drag_bg')[0].style.width = 0 + 'px';
        }
      }
    },
    mounted(){
      this.maxWidth = this.$refs.dragDiv.clientWidth - this.$refs.moveDiv.clientWidth;
      document.getElementsByTagName('html')[0].addEventListener('mousemove',this.mouseMoveFn);
      document.getElementsByTagName('html')[0].addEventListener('mouseup',this.moseUpFn)
    }
  }
</script>
<style scoped>
  .drag{
    position: relative;
    background-color: #e8e8e8;
    width: 226px;
    height: 40px;
    line-height: 40px;
    text-align: center;
    border: 1px solid #ccc;
    border-radius: 4px;
    margin-left: -32px;
  }
  .handler{
    width: 40px;
    height: 38px;
    border: 1px solid #ccc;
    border-radius: 4px;
    cursor: move;
  }
  .handler_bg{
    background: #fff url("") no-repeat center;
  }
  .handler_ok_bg{
    border-top-left-radius: 0;
    border-bottom-left-radius: 0;
    background: #fff url("") no-repeat center;
  }
  .drag_bg{
    background-color: #7ac23c;
    height: 38px;
    width: 0px;
    border-radius: 4px 0 0 4px;
  }
  .drag_text{
    position: absolute;
    top: 0px;
    width: 100%;text-align: center;
    -moz-user-select: none;
    -webkit-user-select: none;
    user-select: none;
    -o-user-select:none;
    -ms-user-select:none;
  }
</style>
